Arithmetic and control unit



FIG. 1 is a perspective view of an arithmetic and control unit showing my new design, wherein a lid portion is in the open position;

FIG. 2 is a top plan view thereof, wherein the lid portion is in the open position; and

FIG. 3 is a top plan view thereof, wherein the lid portion is removed.

Portions of FIGS. 1-3 that are shown as broken lines are for illustrative purposes only and form no part of the claimed design. 

The ornamental design for an arithmetic and control unit, as shown and described. 